Authentication of cinnamon spice samples using FT-IR spectroscopy and chemometric classification

Cinnamon is a popular spice with a lengthy overseas supply chain. C. cassia is commonly traded as cinnamon, but the use of rapid methods to detect its adulteration has not yet been fully addressed. This work explores the use of FT-IR spectroscopy for the detection of adulteration in the cinnamon supply chain by several lower value ingredients. Two species of cinnamon (C. verum and C. cassia) and an adulterant (cinnamon spend, n = 2) were used to create 110 different in-house admixtures. Two different replacement fraud experiments were designed: C. cassia replaced with spend (Scenario A) and C. verum replaced with both C. cassia and spend (Scenario B). Initial analysis by GC-IMS showed promising differences between samples. The FT-IR spectra confirmed significant raw differences in absorbance. PCA for Scenario A demonstrated better separation than in Scenario B. The detection of adulteration of C. cassia (Scenario A) and C. verum (Scenario B) were equality accurate. Classification results showed that the PLS-DA technique was superior to SIMCA for both types of adulteration (PLS-DA: 94-90%; SIMCA: 83-79%, respectively). This demonstrates the potential of FT-IR as a screening method to identify cinnamon adulteration in supply chains and to provide accurate and rapid results without sample preparation.